Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontario L8S 4K1, Canada.
J Neurosci. 2012 May 2;32(18):6373-90. doi: 10.1523/JNEUROSCI.5624-11.2012.
Signal duration is important for identifying sound sources and determining signal meaning. Duration-tuned neurons (DTNs) respond preferentially to a range of stimulus durations and maximally to a best duration (BD). Duration-tuned neurons are found in the auditory midbrain of many vertebrates, although studied most extensively in bats. Studies of DTNs across vertebrates have identified cells with BDs and temporal response bandwidths that mirror the range of species-specific vocalizations. Neural tuning to stimulus duration appears to be universal among hearing vertebrates. Herein, we test the hypothesis that neural mechanisms underlying duration selectivity may be similar across vertebrates. We instantiated theoretical mechanisms of duration tuning in computational models to systematically explore the roles of excitatory and inhibitory receptor strengths, input latencies, and membrane time constant on duration tuning response profiles. We demonstrate that models of duration tuning with similar neural circuitry can be tuned with species-specific parameters to reproduce the responses of in vivo DTNs from the auditory midbrain. To relate and validate model output to in vivo responses, we collected electrophysiological data from the inferior colliculus of the awake big brown bat, Eptesicus fuscus, and present similar in vivo data from the published literature on DTNs in rats, mice, and frogs. Our results support the hypothesis that neural mechanisms of duration tuning may be shared across vertebrates despite species-specific differences in duration selectivity. Finally, we discuss how the underlying mechanisms of duration selectivity relate to other auditory feature detectors arising from the interaction of neural excitation and inhibition.
信号持续时间对于识别声源和确定信号含义很重要。持续时间调谐神经元（DTN）对一系列刺激持续时间有优先响应，对最佳持续时间（BD）有最大响应。在许多脊椎动物的听觉中脑都发现了持续时间调谐神经元，尽管在蝙蝠中研究得最广泛。跨脊椎动物的 DTN 研究已经确定了具有 BD 和时间响应带宽的细胞，这些细胞反映了物种特异性发声的范围。刺激持续时间的神经调谐似乎在听觉脊椎动物中是普遍存在的。在此，我们检验了一个假设，即持续选择性背后的神经机制可能在脊椎动物中是相似的。我们在计算模型中实例化了持续调谐的理论机制，以系统地探索兴奋性和抑制性受体强度、输入潜伏期和膜时间常数对持续调谐响应曲线的作用。我们证明，具有相似神经电路的持续调谐模型可以用物种特异性参数进行调谐，以再现来自听觉中脑的体内 DTN 的响应。为了将模型输出与体内反应相关联并验证，我们从清醒的大棕蝠（Eptesicus fuscus）的下丘脑中收集了电生理数据，并呈现了来自大鼠、小鼠和青蛙的 DTN 文献中发表的类似体内数据。我们的结果支持了一个假设，即尽管在持续选择性方面存在物种特异性差异，但持续调谐的神经机制可能在脊椎动物中是共享的。最后，我们讨论了持续选择性的潜在机制如何与其他听觉特征探测器相关联，这些探测器是由神经兴奋和抑制的相互作用产生的。
